scholarly journals Intramyocellular Lipid Changes in Men and Women during Aerobic Exercise: A 1H-Magnetic Resonance Spectroscopy Study

2003 ◽  
Vol 88 (12) ◽  
pp. 5638-5643 ◽  
Author(s):  
Lesley J. White ◽  
Michael A. Ferguson ◽  
Sean C. McCoy ◽  
HeeWon Kim
Keyword(s):  
Body Composition ◽  
Imaging System ◽  
Vastus Lateralis ◽  
Region Of Interest ◽  
Whole Body ◽  
Resonance Spectroscopy ◽  
Whole Body Imaging ◽  
Intramyocellular Lipid ◽  
Men And Women ◽  
Magnetic Resonance Spectroscopy Study

Abstract This study was designed to compare intramyocellular lipid (IMCL) changes during 60 min of submaximal exercise in men and women. Eighteen moderately active (18–38 yr) men (n = 9) and women (n = 9) were recruited. Maximum oxygen consumption (V̇O2max) and body composition were used to match subjects for aerobic fitness and body composition. Subjects performed cycle ergometry for 1 h at 65% of V̇O2max. Expired gases were collected throughout exercise to determine caloric expenditure and substrate use. Blood samples were collected before and after exercise to evaluate markers of lipid metabolism. Pre- and postexercise proton spectra were acquired from the vastus lateralis using a 3-T whole-body imaging system. Spectra were acquired from an 18-mm3 region of interest (echo time = 45 msec; repetition time = 2000 msec) for IMCL evaluation. IMCL decreased significantly with exercise (11.5–28.5% for men and 17.1–21.7% for women) (P < 0.05); however, there were no significant differences between men and women. Although changes were found for many plasma variables [free fatty acids, glycerol, and norepinephrine (P < 0.05)], group differences were only evident for norepinephrine. In conclusion, a significant decrease in IMCL was observed during 60 min of cycling in matched men and women.

scholarly journals Increased intramyocellular lipid accumulation in HIV-infected women with fat redistribution

2006 ◽  
Vol 100 (2) ◽  
pp. 609-614 ◽  
Author(s):  
Martin Torriani ◽  
Bijoy J. Thomas ◽  
Robert B. Barlow ◽  
Jamie Librizzi ◽  
Sara Dolan ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Body Composition ◽  
Magnetic Resonance ◽  
Subcutaneous Fat ◽  
Abdominal Fat ◽  
Whole Body ◽  
Resonance Spectroscopy ◽  
Intramyocellular Lipid ◽  
Fat Redistribution ◽  
Visceral Abdominal Fat

The human immunodeficiency virus (HIV)-lipodystrophy syndrome is associated with fat redistribution and metabolic abnormalities, including insulin resistance. Increased intramyocellular lipid (IMCL) concentrations are thought to contribute to insulin resistance, being linked to metabolic and body composition variables. We examined 46 women: HIV infected with fat redistribution ( n = 25), and age- and body mass index-matched HIV-negative controls ( n = 21). IMCL was measured by 1H-magnetic resonance spectroscopy, and body composition was assessed with computed tomography, dual-energy X-ray absorptiometry (DEXA), and magnetic resonance imaging. Plasma lipid profile and markers of glucose homeostasis were obtained. IMCL was significantly increased in tibialis anterior [135.0 ± 11.5 vs. 85.1 ± 13.2 institutional units (IU); P = 0.007] and soleus [643.7 ± 61.0 vs. 443.6 ± 47.2 IU, P = 0.017] of HIV-infected subjects compared with controls. Among HIV-infected subjects, calf subcutaneous fat area (17.8 ± 2.3 vs. 35.0 ± 2.5 cm2, P < 0.0001) and extremity fat by DEXA (11.8 ± 1.1 vs. 15.6 ± 1.2 kg, P = 0.024) were reduced, whereas visceral abdominal fat (125.2 ± 11.3 vs. 74.4 ± 12.3 cm2, P = 0.004), triglycerides (131.1 ± 11.0 vs. 66.3 ± 12.3 mg/dl, P = 0.0003), and fasting insulin (10.8 ± 0.9 vs. 7.0 ± 0.9 μIU/ml, P = 0.004) were increased compared with control subjects. Triglycerides ( r = 0.39, P = 0.05) and extremity fat as percentage of whole body fat by DEXA ( r = −0.51, P = 0.01) correlated significantly with IMCL in the HIV but not the control group. Extremity fat (β = −633.53, P = 0.03) remained significantly associated with IMCL among HIV-infected patients, controlling for visceral abdominal fat, abdominal subcutaneous fat, and antiretroviral medications in a regression model. These data demonstrate increased IMCL in HIV-infected women with a mixed lipodystrophy pattern, being most significantly associated with reduced extremity fat. Further studies are necessary to determine the relationship between extremity fat loss and increased IMCL in HIV-infected women.

scholarly journals BONE HEALTH, MUSCLE STRENGTH AND LEAN MASS: RELATIONSHIPS AND EXERCISE RECOMMENDATIONS

2019 ◽  
Vol 25 (3) ◽  
pp. 245-251
Author(s):  
Luciana Duarte Pimenta ◽  
Danilo Alexandre Massini ◽  
Daniel dos Santos ◽  
Camila Midori Takemoto Vasconcelos ◽  
Astor Reis Simionato ◽  
...  
Keyword(s):  
Body Composition ◽  
Muscle Strength ◽  
Lean Mass ◽  
Bone Mineralization ◽  
The Body ◽  
Whole Body ◽  
Body Region ◽  
Level Of Evidence ◽  
Men And Women ◽  
Study Results

ABSTRACT Although muscle strength, lean mass and bone mineral content/density (BMC/BMD) are consistently reported as major outcomes of resistance training (RT), there is still no agreement on the RT regimen that is capable of achieving this result in men and women of different ages. This study describes the effects of RT on muscle strength, lean mass and bone mineralization, highlighting the relationships between them and analyzing the effectiveness of the RT protocol. Information searches were conducted in open access online academic libraries, using the BMC/BMD indices combined with muscle strength, body composition, and resistance exercises. The results showed changes in BMC/BMD in 72% of the studies published in the last decade. Among these, 77% recommended loads ≥ 80% 1-RM, 61% involved older individuals (> 60 years) and 61% had planning protocols of between 3 and 5 months (~12-20 weeks). The results also highlight muscle strength as a promising index of variations in BMC/BMD, with a moderate to high level of association (r2>0.5), which are specific for men and women in relation to the body region with best responsiveness. Among the studies published in last decade, about 61% had protocols involving only RT, and of these, 82% observed combined changes in BMC/BMD, body composition and muscle strength. This review therefore concludes that RT is important for improving muscle strength, increasing lean mass (whole-body and regional) and preventing risk factors that could impair the mineral integrity of the bone tissue, in individuals of all ages and sexes. Level of Evidence I; Systematic review of Level I RCTs (and study results were homogenous).

Validation of whole-body magnetic resonance spectroscopy as a tool to assess murine body composition

2000 ◽  
Vol 24 (6) ◽  
pp. 719-724 ◽  
Author(s):  
P Mystkowski ◽  
E Shankland ◽  
SA Schreyer ◽  
RC LeBoeuf ◽  
RS Schwartz ◽  
...  
Keyword(s):  
Body Composition ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Whole Body ◽  
Resonance Spectroscopy

Progress in n.m.r. zeugmatographic imaging

1980 ◽  
Vol 289 (1037) ◽  
pp. 483-487 ◽  
Keyword(s):  
Imaging System ◽  
Relaxation Times ◽  
Biological Significance ◽  
Whole Body ◽  
Biological Research ◽  
Whole Body Imaging ◽  
Tissue Water ◽  
Imaging Results ◽  
Phosphorus Metabolites ◽  
Test Objects

Applications of nuclear magnetic resonance (n.m.r.) zeugmatographic imaging to medical diagnosis and to medical, physiological, and biological research require the development of appropriate imaging instrumentation and ancillary techniques, as well as an understanding of the biological significance of the imaging results. A whole body imaging system, relying primarily upon reconstruction from projections, is under development in the expectation that the reconstruction approach will be the most practical one for many purposes. In addition, injectable magnetic reagents that can selectively change tissue water relaxation times and image contrast are under development so as to increase the specificity and versatility of the measurements. If very high magnetic fields are employed, 31 P n.m.r. zeugmatography may be practical at very low resolution for human diagnostic studies and for experiments on perfused organs and small animals. Preliminary images, showing the spatial distributions of different phosphorus metabolites in the compartments of test objects, have been obtained at 146 MHz by reconstruction techniques.

scholarly journals Quantitative Imaging in Muscle Diseases with Focus on Non-proton MRI and Other Advanced MRI Techniques

2020 ◽  
Vol 24 (04) ◽  
pp. 402-412
Author(s):  
Marc-André Weber ◽  
Armin M. Nagel ◽  
Hermien E. Kan ◽  
Mike P. Wattjes
Keyword(s):  
Magnetic Resonance ◽  
Diffusion Tensor ◽  
T2 Mapping ◽  
Quantitative Mri ◽  
Whole Body ◽  
Resonance Spectroscopy ◽  
Whole Body Imaging ◽  
Muscle Involvement ◽  
Muscle Diseases ◽  
Proton Mri

AbstractThe role of neuromuscular imaging in the diagnosis of inherited and acquired muscle diseases has gained clinical relevance. In particular, magnetic resonance imaging (MRI), especially whole-body applications, is increasingly being used for the diagnosis and monitoring of disease progression. In addition, they are considered as a powerful outcome measure in clinical trials. Because many muscle diseases have a distinct muscle involvement pattern, whole-body imaging can be of diagnostic value by identifying this pattern and thus narrowing the differential diagnosis and supporting the clinical diagnosis. In addition, more advanced MRI applications including non-proton MRI, diffusion tensor imaging, perfusion MRI, T2 mapping, and magnetic resonance spectroscopy provide deeper insights into muscle pathophysiology beyond the mere detection of fatty degeneration and/or muscle edema. In this review article, we present and discuss recent data on these quantitative MRI techniques in muscle diseases, with a particular focus on non-proton imaging techniques.

Fasting for 72 h increases intramyocellular lipid content in nondiabetic, physically fit men

2002 ◽  
Vol 283 (6) ◽  
pp. E1185-E1191 ◽  
Author(s):  
S. R. Stannard ◽  
M. W. Thompson ◽  
K. Fairbairn ◽  
B. Huard ◽  
T. Sachinwalla ◽  
...  
Keyword(s):  
Serum Insulin ◽  
Vastus Lateralis ◽  
Venous Blood ◽  
Serum Triglyceride ◽  
Plasma Free Fatty Acid ◽  
Resonance Spectroscopy ◽  
Vastus Lateralis Muscle ◽  
Intramyocellular Lipid ◽  
Plasma Ffa ◽  
Intramyocellular Lipid Content

The purpose of this study was to determine changes in intramyocellular lipid (IMCL) content in the vastus lateralis of nondiabetic, physically fit males over 72 h of fasting. Six men, mean age 35 yr (range 23–55 yr), body mass index 23.7 kg/m2 (21.2–27.4 kg/m2), undertook a water-only fast for 84 h. Vastus lateralis IMCL content was determined using proton magnetic resonance spectroscopy after 12 and 84 h of fasting. Venous blood was sampled at 12-h intervals throughout the fast. IMCL-(CH2)n/water and IMCL-(CH2)n/total creatine ratios increased from 0.00623 ± 0.00065 to 0.0142 ± 0.0015 ( P = 0.002) and 6.82 ± 0.87 to 14.96 ± 1.73 ( P = 0.001), respectively. Plasma free fatty acid (FFA), serum triglyceride, and whole blood 3-hydroxybutyrate concentrations increased ( P < 0.001, <0.05, <0.03, respectively), whereas plasma glucose and serum insulin concentrations decreased (both P < 0.001) during fasting. In conclusion, 72-h water-only fasting produces a large increase in plasma FFA concentration, a drop in serum insulin concentration, and accumulation of IMCL in the vastus lateralis muscle of nondiabetic, physically fit men.

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